Duel Fuel means that a radiator or towel rail can be heated by both a heating element and your wet central heating system. This requires a Dual Fuel T Piece and a Heating Element. A set of radiator valves would also need purchasing for this option.

Electric Only radiator or towel rails are as the name suggests, heated only by an electric heating element. This requires Liquid Filling and a Heating Element; both are done at the factory prior to delivery.
No radiator valves are required for this option.